Chuck.



WILLIAM F. REINLIE, OF CHICAGO, ILLINOIS, ASSIGNOR TO ILLINOIS TOOLWORKS, 0F CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

CHUCK.

Specication of Letters Patent.

Patented Jan. 22, 1918.

Application led January 15, 1917. Serial No. 142,343.

To all whom it may concern.'

Be it known that I, WILLIAM F. REINLrE, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented a certain new and useful Improvement in Chucks, of which thefollowing is a specification.

My invention relates to Ichucks for holding abrasive grinding sticks,and the object of the invention is to provide means whereby the grindingstick will be held in the chuc c very securely and yet will not be indanger of being crushed under the holding pressure. It will beunderstood that in tool linishing and for other purposes in the mechanicarts,-

rapidly rotating grinding sticks 0r points are employed. 'lhese sticksor points are subject to breakage if subjected to too great a stress andyet they must be lirinly held, for they commonly rotate at a very highspeed and are frequently forced with considerable pressure against hardmetallicsurfaces. My purpose is, therefore, to provlde a chuck 1n whichthe grinding stick can be firmly bedded and held. Contributory to thisgeneral purpose, it is my object to provide a chuck of this characterwhich shall be simple and elicient in construction and easy tomanipulate.

I obtain my object by the mechanism illustrated 1n the accompanyingdrawings, in which:

Figure 1 is an axial section of a chuck embodying my invention. It showsthe grindin0r stick in position.

4`ig. Q is an end view 0f the left end of Fig. l.

Fig. Fig. 1.

Similar numerals refer to similar parts throughout the several views.

Referring to the drawings, the shank l is of any form suitable forfastening it into the rotating spindle of the grinding machine. At itshead end it has a threaded portion 2 onto which screws a cap 3. At theforward cnd this cap is eonically tapered internally, and preferablyalso externally. lVithin the tapered portion of the cap is a ring 4 oflead or similar material capable of having its configuration changedwhen subjected to pressure. For convenience I will refer to it asplastic although it is less plastic than many substances characterizedby that term. The ring surrounds the body of the grinding 3 is an endview of the right end of and revolve at very high speed and need all thesupport that can be given them, especially. at the front end. In orderto give an especially firm backing at the inner end, the

shank 1 occupies practically the entire cross sectional. area of the cap3 and backs up the grinding stick. Hence there is no possibility for thestick to back away from the work or in any way loosen the grip of theparts. In the form shown the cap is provided with sockets G forreceiving the points of a spanner wrench or other suitable tool by whichthe cap may be rotated.

In operation, the parts are rst loosely assembled in the relativepositions shown in Fig. 1. The ring 4 is originally but slightly largerin internal diameter than the external diameter of the grinding stickand it also approximately fits the internal conical surface of the cap.But as soon as reasonable pressure is exerted to screw the cap onto theshank l, the cap begins to compress the plastic ring onto the grindingstick, the longitudinal motion of the plastic ring being limited by thehead end 0f the shank. Consequently, a comparatively small amount ofturning of the cap after the parts are assembled as tight as they can beby the fingers is sufficient to grip the body of the grinding sticklirmly and thereby secure it so that it will rotate with the chuck. Onaccount of the plastic characteristic of the material of which thecompression ring Ll is formed, the pressure upon the various points ofthe grinding stick is equalized and hence, not only is the grindingstick held very lirmly, but the danger of breaking it by pressure fromthe chuck is eliminated. The device is of simple form and few parts andmay be readily taken apart by simply unscrewing the cap from the shank.

Having thus described my invention, what I claim as new and desire tosecure by Iietters Patent, is:

l. chuck for holding short grinding sticks, said chuck vhaving aninternally tapered cap surrounding the stick, a plastic ring surroundingthe stick and located between the stick andthe cap, and a shank enteringthe back of the cap and forming a backing for both the ring and thestick.

i therefrom at the mouth, a plastic ring between the stick and the cap,the outer end of the ring being substantially iush with the 6116er endof the cap and the inner end of the nasser/i stick being substantiallynsh with the inner end of the ring, and a shank screwing into the hackend of the cap and forming a backing for both the stick and the ring.

3. A chuck for holding short grinding sticks, said chuck having aninternally tapered cap surrounding the stick, a ring surrounding thestick and located between the stick and cap, and a shank entering theback of the cap and abutting corresponding ends of the ring and stick.

In witness whereof, I have hereunto subscribed my name. v

WILLIAM F.'HREINLIE

